This invention relates to a silver halide photographic material and more particularly to a silver halide photographic material capable of keeping an dye image stable against heat and light and preventing a stain occurring.
It has so far been well-known that a silver halide color photographic material is exposed imagewise and color-developed, and thereby the oxidation products of a color developing agent and a color forming agent are reacted couplingwise with each other to produce such a dye as indophenol, indoaniline, indamine, azomethine, phenoxadine, phenazine and the like, so that a color image may be produced. In such a system as described above, a color reproduction is normally carried out in a substractive color process and there uses a silver halide color photographic material comprising blue-sensitive, green-sensitive and red-sensitive silver halide emulsion layers respectively containing complementary-color forming agents, namely, yellow, magenta and cyan color forming couplers.
The couplers which are to be used for forming the above-mentioned yellow color-image include, for example, an acylacetanilide-type coupler; the well-known couplers for forming a magenta color-image include, for example, a pyrazolone-, pyrazolobenzimidazole-, pyrazolotriazole- or indazolone-type coupler; and the couplers for forming a cyan color-image include, for example, a phenol- or naphthol-type coupler which is generally used.
It is desired that such a dye image obtained as above may neither be discolored nor be faded even if it should be exposed to light for a long time or preserved in a high temperature and humidity condition. With respect to a silver halide color photographic material (hereinafter called a color photographic material), it is demanded that the color-undeveloped areas thereof shall not be yellowed (hereinafter called Y-stain) by light or at a high humidity and temperature.
In the case of using a magenta coupler, however, such a Y-stain caused in a color-undeveloped area at a high humidity and temperature or a discoloration caused by light in a dye-image area are more serious than those caused in the case of using a yellow or cyan coupler. This problem has often led to an issue of color reproductions.
The couplers being popularly used to form a magenta dye include, for example, a 1,2-pyrazolo-5-one. It is a serious problem that the dyes prepared of the 1,2-pyrazolo-5-ones have a main absorption around 550 nm and besides a by-absorption around 430 nm. Therefore, various studies have been made to solve this problem.
The 1,2-pyrazolo-5-one type magenta couplers each having an anilino group in the 3rd position are especially useful for obtaining a color image for print use, because they are less in the above-mentioned by-absorption. The above-mentioned techniques are described in, for example, U.S. Pat. No. 2,343,703, British Patent No. 1,059,994 and the like.
Meanwhile, the above-mentioned magenta couplers have the disadvantages that the image preservability and particularly the fastness of dye images to light are seriously poor and that Y-stains in color-undeveloped areas are also serious.
The other means have been proposed for reducing the above-mentioned by-absorption around 430 nm from the magenta couplers. They include, for example, such a magenta coupler as a pyrazolobenzimidazole described in British Patent No. 1,047,612; and indazolone described in U.S. Pat. No. 3,770,447; an 1H-pyrozolo[5,1-c]-1,2,4-triazole type coupler described respectively in U.S. Pat. No. 3,725,067 and British Patent Nos. 1,252,418 and 1,334,515; an 1H-pyrozolo[1,5-b]-1,2,4-triazole type coupler described in Research Disclosure No. 24531; an 1H-pyrazolo[1,5-c]-1,2,3-triazole type coupler described in Research Disclosure No. 24626; an 1H-imidazo-[1,2-b]-pyrazole type coupler described respectively in Japanese Patent O.P.I. Publication No. 162548/1984 and Research Disclosure No. 24531; an 1H-pyrazolo[1,5-b]pyrazole type coupler described in Research Disclosure No. 24230; an 1H-pyrazolo[1,5-d]tetrazole type coupler described in Research Disclosure No. 24220; and the like. The dyes each prepared from the 1H-pyrazolo[5,1-c]-1,2,4-triazole type coupler, an 1H-pyrazolo[1,5-b]-1,2,4-triazole type coupler, an 1H-pyrazolo[1,5-c]-1,2,3triazole type coupler, an 1H-imidazo [1,2-b]pyrazole type coupler, an 1H-pyrazolo[1,5-d]pyrazole type coupler and an 1H-pyrazolo[1,5-d]tetrazole type coupler; such a dye as given above has the desirable advantages that it is preferred for color reproduction because the by-absorption thereof around 430 nm is remarkably less, and a Y-stain caused in color-undeveloped areas by light or at a high temperature and humidity is extremely less, as compared with the above-mentioned dyes each prepared of a 1,2-pyrazolo-5-one having an anilino group in the 3rd position.
However, the azomethine dyes prepared of the above-mentioned couplers are very poor in fastness against light and in addition they are apt to be faded by light, so that they will worsen, to a marked degree, the characteristics of a color photographic material, especially those for print use. Therefore, they have not yet been put in practical use.
In the meantime, Japanese Patent O.P.I. Publication No. 125732/1984 proposes a technique in which the light fastness of a magenta dye-image obtained from an 1H-pyrozolo-[5,1-c]-1,2,4-triazole type magenta coupler may be improved by jointly applying a phenol type compound or a phenylether type compound to an 1H-pyrazolo[5,1-c]-1,2,4-triazole type magenta coupler. Even this technique is still not fully satisfactory to prevent the light fading of the above-mentioned magenta dye-image and, in addition, it was found that such light discoloration prevention is nearly impossible.